Base for electric lamps



Aug. 12, 1941. D. K. WRIGHT 2,252,476

BASE FOR ELECTRIC LAMPS Filed Nov. 29, '1940 1|||Ill 1||H| I I IIIIII l I "'i% yaw w 'I/IIII lnvervtor: DanieL K. Wright bid ,Mm

His At'kor'neg.

Patented Aug. 12, 1941 UNITED STA BASE sou. amormo Daniel K. Wright, Cleveland Heights, Qhio, as-

signoito General Electric ilcmpany, a ra= tion of New York 4i Claims.

My invention relates to electric incandescent lamps and similar devices comprising a bulbdevices such as described and claimed in my,

Patents Nos. 2,148,314 and 2,148,315, issued February 21, 1939.

One objectof my invention is to provide a base for electrical devices of the above type which is simple in construction and inexpensive, and which is firmly secured to the envelope or the device without the use of the usual basing cement.

Another object of my invention is to provide an electrical device having a base firmly secured to a curved or convex surface of the envelope of such device and effectively locked against lateral and rotative movement thereon, the base being secured to the envelope by mechanical means.

Further objects and advantages of my invention will appear from the following description of a species thereof and from the accompanying drawing in which:

Fig. 1 is a side elevation, partly in section, of an electric incandescent lamp provided with a base comprising my invention; Fig. 2 is a fragmentary rear elevation, partly in section, of the lamp shown in Fig. 1; and Fig. 3 is a perspective view of the lamp base itself.

Referring to the drawing, the invention is there shown in connection with an electric incandescent projector lamp of the sealed beam" type such as described and claimed in the abovementioned patents. The lamp comprises a sealed glass bulb or envelope I consisting of a preformed pressed glass concave reflector section II of heat-resisting glass, and a cover glass or lens section i2, also of heat-resisting pressed glass,

sealed-together by fusion. The interior surface i3 of the reflector section II is of any suitable shape, preferably that of a paraboloid, and is covered with a reflecting metallic coating I4,

' preferably aluminum, so as to form a reflecting having substantially parallel portions extending through Milli iii in reflector section on opposite sides of the vertex roof. Glass bosses it concentric with said i; it are provided on the exterior or rear surface of said reflector section. The envelope to n ousted and with a suitable gas by of an exhaust tube 2% attached to the reflector section it at its vertex, i. e... at a point between the openings it. After the gas fllling is introduced into the lamp envelope, the exhaust tube ilfl is tipped ed, as shown in the drawing.

The leading-in wires lit, il, ertterlorly of the envelope it), are hermetically united, preferably by brazing, to metal cups or thimbles 2 i, ii having their es or rims fused to and sunk and embedded in the thickness of the glass bosses ill surrounding the openings 88. A hermetic seal is thus provided between the leading-in wires and lamp envelope similar to that described and claimed in my Patent No. 2,098,080, issued November 2, 1937. The cups or thimbles M are made of a metal to which the glass of the lamp envelope will wet" or stick, and should preferably have the same expansion as the glass, as near as may be. For heat-resistant glass of the type known as Pyrex," the cups at are preferably made of an iron-nickel-cobalt alloy known as Fernico.

Mounted on the curved rear surface 22 of the reflector section It, at the apex thereof, is a base 23 according to the invention comprising a molded hollow body member or shell 24 of suitable insulating material, such as Bakelite. The shell is open at its inner end and is formed with a flattened oval portion 25 having semi-circular curved ends fitting snugly over the bosses IS on the reflector section H, as shown particularly in Fig. 2. The outer end of the shell is closed by an end wall 25 which is connected to the oval shaped wall portion 25 by tapering flat and .curved side wall portions 21 and 28 respectively.

The rim or edge 28 of the base shell 24 is suitably curved, as shown in Fig. 1, to conform to the curvature of the rear surface 22 of the envelope. In addition, the rim or edge is beveled or rounded inwardly, as shown'at 30 in Fig. 1, to provide clearance for the fillets at the bases of the glass bosses l9 and thus permit the base shell to fit down onto the curved rear surface 22 of the lamp envelope.

Molded in the outer surface of the base shel 24, so as to be flush therewith, are a pair of metal strips 3! forming the terminals of the base. The strips 3| are molded in the opposite ends of the end wall 28 and have bent portions 32 extending along and molded in the tapering curved .side walls 2!. The leading-in wires i0, I! are electrically connected to the metal terminal strips II, the said wires extending through suitable fastened to the strips by solder 33 or other suitable means. Suitable fastening screws 34 are threaded into the bent portions 32 of the metal bosses to therebylock said member against lat era] and rotational displacement on said bulb,

and leading-in wires hermetically sealed in said bulb and fixedly secured at their outer ends to said base contacts, said leading-in wires being tightly stretched between said bulb and base and constituting the sole means for securing said base firmly to said bulb against the said convex wall thereof.

strips to provide attachment means for the electrical connections.

The base 23 is secured to the lamp envelope ll solely by the relatively heavy leading-in wires i6, II, no basing cement being used for attacha ment purposes. The said wires are stretched tightly between the metal cups 2| and the end wall of the lamp base, thereby securely 'holding the base on thecurved apical portion of the lamp envelope ll. Lateral and rotative shifting of the base on the lamp envelope is entirely prevented by the engagement between the semi-cir- 3. An electrical device comprising a sealed bulb having a concave reflector portion formed as a surface of revolution and provided with spaced bosses on its outer convex surface ad- Jacent the apex thereof, an electrical energy translation element mounted within said bulb in definite optical relation to said reflector portion, a basemounted on the apical portion of said bulb, said base comprising a hollow body member of insulating material provided with metal contacts and having its inner end open and shaped to conform-to and engage the convex outer surface of said bulb at the apex thereof and to fit snugly around said bosses. to thereby lock said cular ends of the oval shaped base shellportion II and the glass bosses I! on the lamp envelope.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electrical device comprising a sealed bulbhaving a convex outer wall portion provided with spaced bosses on the surface thereof, a base comprising a hollow body member of insulating material provided with metal contacts and having an open end fitting snugly around said bosses to thereby lock said member against lateral and rotational displacement on said bulb, and leading-in wires hermetically sealed in said bulb and fixedly secured at their outer ends to said base contacts, said leading-in wires being tightly stretched between said bulb and base and constituting the soiemeans for securing said base firmly to said bulb.

2. An electrical device comprising a sealed bulb having a convex outer wall portion provided with spaced bosses on the surface thereof, a base comprising a hollow body member of insulating material provided with metal contacts and having an open end shaped to conform to and engage said convex bulb wall and fit snugly around said member 'againstlate'ral and rotational displacement on said bulb, and leading-in wires hermetically sealed in said bulb and electrically connected at their inner ends to-said translation element and at their outer ends to said base contacts, said leading-in wires being tightly stretched between said bulb and base and constituting the sole means for securing said base firmly to said bulb against the convex outer surface at the apex thereof.

4. A base for attachment to the envelope of an electrical device comprising a molded hollow body member of insulating material closed at one end by an end wall, andlmetal terminal elements molded into the outer surface of said end wall and each having an opening in alignment with openings in said end wall so as to communicate with the interior of said body member, the wall of said body member adjacent the open end thereof being formed inthe shape of a flattened oval with substantially semi-circular ends and the rim of said body member being shaped to conform to the curvature of the wall of said envelope.

DANIEL K. WRIGHT. 

